1. Field of the Invention
The invention relates to a control apparatus and a control method for a vehicle.
2. Description of Related Art
With the recent increase in environmental protection awareness, the popularity of hybrid vehicles (HVs), electric automobiles (EV), and so on that have a motor installed as a drive source is becoming ever greater. Often in such vehicles, an alternating current motor is driven using a direct current power supply such as a lithium ion battery or another type of secondary battery as a power source.
When an alternating current motor is driven using a direct current power supply, as described above, an inverter is typically used to convert direct current power into alternating current power. Storage means (a condenser, a capacitor, or the like, for example) are provided at an input stage of the inverter, or in other words on the direct current power supply side, to smooth an output of the direct current power supply. Further, means (a relay or the like, for example) are typically provided between the direct current power supply and the inverter to open and close an electric connection between these two components. During an operation performed on the inverter or the motor for the purpose of maintenance, inspection, repair, and so on, the relay is opened prior to the operation to disconnect the inverter or the motor from the power supply. Further, when a charge is stored in the storage means provided at the input stage of the inverter, the aforementioned operations may be difficult, and therefore the charge must be discharged from the storage means after switching the relay OFF.
Discharging the storage means only when a rotation speed of the motor has fallen to or below a predetermined rotation speed has been proposed in the related art (see Japanese Patent Application Publication No. 2010-130845 (JP-2010-130845 A), for example).
When a vehicle installed with a motor as a drive source collides such that the vehicle is in an overturned condition or the like, for example, the motor may continue to rotate as tires spin and so on. Likewise in this condition, the charge needs to be discharged from the storage means quickly after opening the relay between the direct current power supply and the inverter in order to perform an operation, for example.